/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hama.bsp.message.compress;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.util.ReflectionUtils;

public class BSPMessageCompressorFactory<M extends Writable> {

  public static final String COMPRESSION_CODEC_CLASS = "hama.messenger.compression.class";

  /**
   * Returns a compressor via reflection based on what was configured.
   * 
   * @param conf
   * @return a compressor that was configured.
   */
  @SuppressWarnings("unchecked")
  public BSPMessageCompressor<M> getCompressor(Configuration conf) {
    if (conf.get(COMPRESSION_CODEC_CLASS) != null) {
      try {
        return (BSPMessageCompressor<M>) ReflectionUtils.newInstance(conf
            .getClassByName(conf.get(COMPRESSION_CODEC_CLASS,
                Bzip2Compressor.class.getCanonicalName())), conf);
      } catch (ClassNotFoundException e) {
        e.printStackTrace();
      }
    }
    return null;
  }
}
